The present invention is directed in general to insertion guides for medical instruments, and in particular to an interuterine sheath for insertion of medical instruments, such as hystoscopes into the uterus for providing various diagnostic and/or therapeutic procedures thereto.
In the prior art, a certain amount of longitudinally directed insertion force has been required to permit insertion of medical instruments through the internal diameter of the cervix and into the uterus. This required force is necessitated by reason of annularly disposed and gripping musculature within the cervix to urge the cervix into its normally closed (i.e., non-dilated) position. Accordingly, an initial amount of force has been necessary to penetrate the cervical opening with such medical instruments, such as the hystoscope. However, after such initial penetration, the amount of force necessary to slide the shaft of the medical instrument into the uterus is of a much lesser amount. In addition, the uterus is relatively short in its longitudinal dimension. Thus, the risk of perforation of the uterus wall during such insertion of a medical instrument is present.
Also, it is necessary to maintain a field of irrigation fluid within the uterus both for irrigation and visualization purposes. In prior art techniques, there were problems of fluid blockage of irrigation fluid ports on the hystoscope caused by the wall of the cervix. This also created a tendency for perforation of the uterus during movement of the instrument shaft to maintain flow of the irrigation fluid. The risk of perforation is also created in situations where the surgeon must move the treatment devices further into the uterus in order to facilitate perpendicularly evacuating fluid removal mechanisms to clear past the walls of the cervix.
In addition, the insertion guide of the present invention has a length which is not longer than that of the internal longitudinal dimension of the cervix, and thus will not extend the full length of the uterine cavity. As a result, when the invention is used for insertion into and thereby partial dilation of the cervix, there is no substantial danger created thereby of perforation of the uterus.
Accordingly, once the interuterine guide of the present invention is disposed into operative position within the cervix, the medical instrument can be inserted, removed and reinserted without substantial risk of perforation, because, inter alia, the need for redialation of the cervix during the course of the operation/surgery is eliminated.
Finally, with current devices, there is great difficulty in accounting for the volume of the irrigation fluid. However, with the structure of the present invention, all exiting fluids enter a central collection system, thus allowing the volume of the exiting irrigation fluid to be compared with the volume of the entering fluid, in order to determine the amount of loss of irrigation fluid into the body that may have occurred during the operation. With current systems, this function is not possible, because all of the exiting fluid does not enter a central collection and monitoring system.
By discharging irrigation fluid in a direction parallel to the longitudinal channel of the internal diameter of the cervix, the structure of the present invention also eliminates the prior art problems associated with blockage of the fluid removal path by the wall of the cervix. In addition, the structure of the present invention reduces the risks associated with cervical dilation (i.e., by holding the cervix in an operatively semi-dilated position, the structure hereof eliminates the need to re-dilate the cervix during operative procedures). In addition, these structures of the interuterine guide tube of the present invention allow for accountability of the irrigating fluid used during the course of an operation.
In addition to the above advantages, further advantages of the interuterine guide tube apparatus of the present invention will become known to those ordinarily skilled in the art upon review of the following summary of the invention, the brief description of the drawing, the detailed description of preferred embodiments, the appended claims, and the accompanying drawing.